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Home , Albatross, Laysan albatross, Procellariiformes

PlumaDevariation and hybridizationin Black-footedand LaysanAlbatrosses

Tristan McKee P.O. Box631 Ferndale, 95536 (eraall:bertmckee•yahoo.com)

PeterPyle 4990Shoreline Highway SUnsonBeach, California 94970 (email:[email protected])

INTRODUCTION Black-footed(Phoebastria nigripes) and (P. immutabilis) nest sideby sidein denseisland colonies. Their breeding populations center in the northwesternHawaiian Islands, with smaller colonies scattered across the subtrop- icalNorth Pacific. Both visit nutrient-rich waters off the west coast of North Americathroughout the year to forage. Black-footeds concentrate in coastal waters fromnorthern California tosouthern , while Laysans frequent more offshore andnortherly waters in thisregion. Bkders on pelagic trips off the West Coast often encountersignificant numbers of oneor bothof thesespecies, and searching for other,rarer albatrosses among them has proven to be a worthwhile pursuit in recen! years(Stallcup and Terrill 1996, Cole 2000). Albatrossesidentified as Black-looted x Laysan hybrids have been seen and studiedon MidwayAtoll and other northwestern Hawaiian Islands since the late 1800s(Rothschild 1900, Fisher 1948, 1972). In addition,considerable variation in appearanceis found within both species, indMduals with strikinglyaberrant plumageand soft part colors occasionally being encountered (Fisher 1972, Whittow 1993a). hosts approximately two-thirds of the world'sbreeding A presumedhybrid Laysan x Black-lootedAlbatross tends a chickat Midway LaysanAlbatrosses (Fig. 1) andone-third of theworld's breeding Black-footed Atoll, 14 February2000. Photographby PeterPyle. Albatrosses.These populations have provided us with many opportunities tostudy andphotograph presumed hybrids and unusual individuals. In this paper, we dis- BLACK-FOOTEDALBATROSS cussvariation in theplumages of bothspedes and the appearances of aberrant Worldwide,the Black-looted isthe less common of thetwo species, with indMdualsand probable hybrids, as well as the potential pitfalls to identificationpopulation estimates ranging from 200,000 to 300,000 individuals (Whittow 1993a, thatsuch may pose. Our observations arebased on a collective21months on Cousins& Cooper 2000). Adults arrive at colonies in lateOc!ober, fledging takes Midwayfrom 1997 to 2000,in additionto the study of thousandsof Black-footed place in late June and July, and adults have an incomplete tocomplete molt during andhundreds of LaysanAlbatrosses at off California. April(non-breeding individuals) or July (breeders) through October. This species islargely dark brown at all ages, with white shafts to the outer primaries. Juveniles havewhitish bases to the encircling the bill and to those feathers in a cres- centimmediately under the eye. The resulting pale areas are obscured at fledging, resultingin wholly dark (Fig. 2) butquickly become visible with wear. Fledglingsusually show well-developed white areas on the face by the time they reachNorth America in latesummer. We have seen one or two breeding adults that lackedthe eye crescent and showed limited white around the bill, but these features areobvious on the vast majority of individualsafter fledging. edges on the headbecome very frayed and bleached on birds of alllater ages in the summer, and thewhite area can encompass most of thehead on some birds in thisstate (Fig. 3). Adultswith heavily bleached heads from April to August likely represent breeding individualsthat have spent significant time at subtropical latitudes, whereas those showingless bleaching probably are prebreeders (ages 2-10 or moreyears) or birds thatskipped breeding that year and remained attemperate or subarcticlatitudes, thusbeing exposed toless intense sunlight. Feather edges throughout the neck and underpartsalso become bleached and frayed, and on manybirds the edges contrast distinctlywith dark feather bases and create a scalloped look of tanon brown (see Miller 1940). Figure1. MidwayAtoll hosts significant portions of thebreeding populations of Whiteleathering develops on therump, uppertail coverts, lower belly, vent, and bothBlack-looted and Laysan Albatrosses. Presumed hybrids and aberrant indi- undertailcoverts, and its extent has been linked to age and sex (Streets 1877, Bourne vidualsare found regularly in these dense colonies. Photograph byPeter Pyle. 1982,Pyle unpubl. data), old males being whitest. Birds showing areas of white

VOLUME 56 (2002), NUM.ER 2 131 Figure2. JuvenileBlack-tooted Albatross near fledging. Pale areas are Figure3. Anexceptionally worn and bleached adult Black-tooted Albatross. alreadydeveloping on the face, before all the downis lost.Midway Atoll, Thebill is nearthe paleextreme for the species.Photographed in Monterey June1999. Photographby PeterPyle. Bay,off SantaCruz, California, 15 October2000. Photograph by Michael Donahue.

Figure4. A strikingleucistic Black-tooted Albatross in MontereyBay, California,18 September1988. The bill shape eliminates Southern Giant- Petreland ; the birdalso shows a shadowof the Black-toot- ed'sfacial pattern. Photograph by SergeLaFrance.

Figure5. A leucisticBlack-tooted Albatross on , , January Figure6. Leucismoften appears in patches,as in thisBlack-tooted with 1993. Bocumenteddetails of the wingand tail patternindicate that this is whiteouter primaries and a whitestrip across the belly;note also the pale the sameindividual as presentedin Figure4, photographedseveral years splotchingon lhe feet. The facial pattern is typicalof adults.Midway Atoll, earlier.Photographs from U.S. Fishand Wildlife Service files. 23 June2000. Photograph by PeterPyle.

132 NORTH AMERICAN BIRDS Black-lootedand LaysanAlbatrosses

elsewhereonthe body due to leucism are very rare but have been photographed in severallocations (e.•, Figs.4, 5, and6). In extremecases, such as the mostly white birdin Figures4 and 5, this can create an appearance reminiscent of a light-morph SouthernGiant- (MacroheRes giganteus). The distinctivebill structureof MacroheReswith external nasal tubes atop the culmen, consistently distinguishes thisgenus from all albatrosses (Harrison 1983). Roberson (1980) mentioned white in therectrices and light dusky-yellow feet on some birds. We have seen pale col- orationin theseareas only on obviouslyleudstic Black-footeds, soit doesnot appearto be age-related.Similarly, pale underwings apply only to presumed hybridsand leucistic birds in ourexperience. Such birds were noted by Stallcup (1976),who felt that it wasage-related, and by Roberson (1980), who considered it a featureof aberrantbirds or hybrids.The appearance of indistinct pale areas can alsobe created by the exposure of featherbases of birds in heavymolt in earlysum- meen TheBlack-footed's billis blackish, usually with a pinkishtinge of varyinginten- sityat the base. This color is well developed in some individuals of both sexes, mak- ingthe bill appear fairly bright pink with a blackishor darkgray nail (Fig. 3), espe- Figure7. JuvenileLaysan Albatross, showing white auriculars; adult bill color ciallyin brightsunlight. Pink-billed birds may cause confusion with juvenile Short- beginsto developnear fledging. Midway Atoll, June 1999. Photograph by tailedAlbatross (P.. albatrus), which has a considerablylarger bill. The bill of Short- PeterPyle. tailedis dark at fledging (H. Hasegawa, pers. comm. to Pyle), but eventually it devel- opsa brightpink base and pale blue tip. The timing of thischange is unknown. Largelydark, pink-billed birds photographed off Californiain Octoberto Decemberhave been regarded asjuveniles (e.g., Stallcup and Terrill 1996, N.A.B. 52: 203),but these birds show worn, retained feathers, suggesting that the second pre- basicmolt has taken place. Pink-billed birds photographed in Oregon in March (N..A.B.55: 506) and California in lanuary(McKee and Erickson, in press) may in factbe juveniles, but ageing criteria in thisspedes are still undeaen Short-tailedAlbatrosses slowly acquire an extensively white adult plumage (cf. Roberson1980, Erickson and Hamilton 2001). Pale areas on the upperwing coverts canbe among the first signs of this transition in Short-tailed,but it shouldbe noted that the innermostgreater coverts, tertials, and humeralson Black-looted Albatrosseshave paler inner webs. When worn, this patch of featherscan contrast withthe remainder of theupperwing, creating an appearancesimilar to Short- tailed.Leg and foot color of Black-lootedusually isblackish or darkgray. We have foundseveral individuals with irregular pale splotching on thelegs and feet (e.g., Fig6; thesebirds often show ieucistic plumage as well), but in no casewas this extensiveenough to resemble the entirely pink feet of juvenile Short-taileds.

LAYSANALBATROSS Figure8 A Laysanwith rather pale underwings, showing narrow black margins.Midway Atoll, May 1999. Photographby Tristar/McKee. Althoughabout ten times more numerous than the Black-looted Albatross, with a worldpopulation estimated at 2.5 millionbirds (Whittow 1993b), the Laysan Albatrossisnot encountered asfrequently dose to theNorth American continent. Laysansalso arrive at breeding colonies inNovember, fledge young in Julyand early August,and have an annual incomplete tocomplete molt from April to October. Thisspecies was named immutabilis, meaning unchangeable, because of itslack of obviouslydifferent innnature and adult (Jobling 1991). While it is true thatage-related variation is subtle,this species nonetheless shows a considerable amount of individual variation. Laysansatfledging are white throughout the head and underparts, with a small blackpatch surrounding the eye (Fig. 7). They lack the gray wash across the auric- ularsof adultbirds (Fig. 8). Theexact time at whichgray in theface develops is unknown. typically do not molt between fiedging and the second prebasicmolt (see Howell and Cotben 2000) during the following breeding season, so grayauriculars are not likelyacquired before then. Our observationsoff Californiaconfirm that juveniles can remain white-faced at least until Decembeen Thegray wash normally isquite evident, though variable, by the time birds return tocolonies, many of which are three to four years old (bands examined). Ageing is notalways straightforward atsea, because the gray wash of adults can be difficult to Figure9. A Laysantoward the darkend of the spectrum,with blackareas discerninbright sunlight. Itsextent also is reduced by wear, and some birds take on mergingon the underwings.Midway Atoll, February 2000. Photographby afacial pattern like that of thejuvenile by late summer,just before the prebasic molt. Tristan McKee. Theheavily worn mantle feathers of thesebirds readily distinguish them from fresh

VOLUME 56 (2OO2), NUMBER 2 133 juveniles.All ageshave a darkbrown back, upperwings, and rearices and show whiteshafts to the outer primaries. The bill is dark grayish on young chicks, but a dullpink base and bluish-gray nail begin to develop before fledging. Theunderwing pattern of this species usually isdistinctive, butthere is substan- tialvariation in theamount of blackversus white (National Geographic Society 1999,Sibley 2000). Preliminary observation of known-age birds on Midway has indicatedthat underwing variation isnot strongly related to age, but more study is neededto confirm this. Black is present on the leading edge of the underwing, the flightfeathers, the primary coverts, and usually ina triangular patch on the humer- als.Near the palest extreme for birds that otherwise appear normal (but cf. leucis- ticbirds), the black borders are very narrow and the humeral patch limited to a few blackishstreaks ora grayish shadow. The humeral patch is absent or invisible inthe fieldon a fewbirds, which appeared torepresent less than 0.01% of the overall pop- ulationat Midway.They couldcreate confusion with the ShyAlbatross (Thalassarchecauta) complex (Cole 2000), but size, structure, and bill shape differ- Figure10. A leucisticLaysan Albatross, near fledging at MidwayAtoll 25 encesare easily visible and should be usedto confirmany in the June1999. One or two mostlywhite chicks are found almost every year on North Pacific. Midway.Photograph by Peter Pyle. Towardthe darker side of the underwing spectrum, the black areas merge, some- timesto theextent that white is limited to theouter secondary coverts (Fig. 9, cf. Fig.20). A fewindividuals show no whiteon theunderwing, with either a gray shadowof thelatter pattern or entirdy dark underwings. It is not known whether theseare at the dark extreme for the species or if thisis strictly the result of intro- gressionwith the Black-footed Albatross (see bdow). The amount of darkon the rumpis also variable and often loosely mirrors that of theunderwing. The darkest birdshave a darkrump with only a thinU-shaped white area on theuppertail coverts,contrasting with the dark tail, while the palest show a straightline of con- trast,even with the trailing edge of thewings, between the dark back and an entire- lywhite rump. Most birds fall between these two extremes, showing a patchy dark areaextending into the center of an extensively white rump (Fig. 20). Laysans show a variableamount of dark smudging around the thighs, which is discussed bdow. Asin Black-footeds,leucism and other plumage aberrancy isoccasionally noted In Laysans.One or twomostly white chicks (e.g., Fig. 10) are found on Midway almostevery year, and some have been followed to fledging,but none have been knownto returnas adults. These birds again could cause confusion with giant- petrelsuntil bill structure isnoted. Bill structure also is an important feature for determiningwhich of the Phoebastria isinvolved when dealing with leucistic birds: Figure11. LaysanAlbatross chicks showing a scalyor barredpattern to the withexperience, theshorter, thicker bill of Black-footed isdistinguishable inthe fidd upperparts,another regular occurrence in largecolonies. The on theleft fromthe relatively slimmer bill of Laysan,which shows a more concave culmen (cf. wasphotographed at Midway Atoll, 21 May1997, the bird at right30 May Figs.6 and13). Figures 11, 12, and 13 illustrate some of theother ways leucism 1993.Photograph by Peter Pyle (left) and from U.S. Fishand Wildlife Service and/orother types of plumage aberrancy can be manifested in this species. A vari- files(right). ablean•ount of gray or whitish in the mantle feathers, often in a uniformpattern, is themost commonly encountered example. This can involve a scaly pattern of con- trastingfeather edges, various internal bars, or darkanchor-shaped markings on pale-basedfeathers. Fisher (1972) described such birds, and we have found a small numberregularly on Midway. Such plumages may be caused by schizochroism (the lackof a pigmentthroughout) ordilution (reduction in quantity of a pigment),but thespecific cause is difficultto determinewithout precise genetic information (Buckley1969; E A. Buckley,pets. comm.). Indistinctwhite bars on dark feathers are particularly common inchicks (Fig. ! 1) andmaybe exaggerated growth bars resulting from metabolic changes during feath- ergrowth (see Michener and Michener 1938). The adult in Figure12 takes gray in themantle to theextreme. Several aberrant Laysans on Midway have returned to specificareas year after year, retaining the same patterns ofabnormal pigmentation throughrepeated molts. Theunusual coloration of thebird in Figure13 is evident in boththe plumage andthe soft partx The bill is exceptionally bright pink, the gray wash is lacking on theface, and the upperparts show a considerableamount of white. This bird super- Figure12. Aberrant Laysan Albatross. Such birds can show a palegray shadow ficiallyresembles a near-adult Short-tailed Albatross in coloration, but size and of thetypical Laysan underwing pattern of darkmargins and humerals. Midway structuralfeatures identify it readily. Atoll,April 1993. Photograph from U.S. Fishand Wildlife Service files.

134 NORTH AMERICAN BIRDS Black-footedand LaysanAlbatrosses

HYBRIDS In 1997-2000,we observedup to 20 differentpresumed first-generation (F]) hybridson Midway.Although no between these species has yet been con- firmedgenetically or throughparentage, presumed hybrids are intermediate betweenBlack-looted and Laysan in plumage,soft-part, behavioral, and vocal char- acters(Fisher 1972), and they would be difficult to explain as resulting from varia- tionin eitherparental species. As also reported by Fisher(1972), all presumed hybridswe observed were interacting with Laysan Albatrosses, many being found amongthe pure Laysan populations in the central portions of theislands. We have witnessedmale Black-looted Albatrosses involved in "rapes"(Fisher 1971) of femaleLaysans, and, contra Fisher ( 1948,1972), we believe that hybrids between the twospecies are most likely products of theseextra-pair copulatory events rather thanof naturallyoccurring mixed pairs, something we have seen no evidence of on Midway.This would explain why hybrids seemed to beimprinted upon Laysan ratherthan Black-looted Albatrosses: they were likely raised by a pairof Laysans, themale unwittingly not the father. We have seen occasional attempts at interspe- cificcourtship dancing, but these rarely lasted more than a fewseconds (see also Whittow1993b). It shouldbe noted, however, that Fisher (1971) examined Laysans afterintraspecific extra-pair copulatinn and found no physical evidence of success- fidcopulation. Becauseof the intermediate nature of their displays, most attempts of hybridsat courtshipwith Laysans appear unsuccessful. Weobserved two presumed hybrids incubatingeggs and raising chicks with Laysan mates during the 1999-2000 season (frontispiece);hybrids have been observed on on several other occasions. The chicksfrom these pairings appeared to havethicker bills and darker first-basic plumagethan Laysan chicks from adjacent nests. Blood from hybrids and these apparentF2 (second-generation)back-crosses hasbeen taken by U.S. Fishand Wildlifebiologists for DNA sampling (N. Hoffman,pers. comm.). If confirmed, thiswould represent the first documented record of a hybridalbatross successfully breeding(cf. Whittow 1993b), although our observations of suspected back-cross- es(see below) indicate that this probably has occurred before. Actual parentage is difficultto confirm in the field because"adoption" ofvarious objects, indudlng dis- placedeggs and young chicks, iscommon in thesedense colonies. Mostpresumed FI hybridsare quite distinctive, with strong gray tones setting themapart from both species (Figs. 14, 15, 16, 17). Structural and behavioral fea- Figure13. ThisLaysan shows reduced pigment in boththe plumageand soft tures,soft part colors, courtship displays, and vocalizations arevariably intermedi- parts;note the superficialresemblance to a subadultShort-tailed Albatross ate.The head and neck are gray on most birds, varying from a palepearl gray to a MidwayAtoll, 8 February2000. Photograph by PeterPyle. dark,smoky-brown color. White areas around the bill and under the eye are often moreextensive and diffused atthe edges than on fresh Black-footeds, giving the face a frostyappearance. The gray wash on the neck can give way to white on the breast or continuedown onto the lower breast, sides, and flanks. The undertaftcoverts and lowerflanks often show some dark gray, even on pale hybrids. A large white area remainson the belly, usually more extensive than on Black-footeds. Thegrayish head and underpart color of evenmost dark hybrids, such as the birdin Figure16, is distinguishable from the dark brown of Black-foote&Figure 19 showsthe only hybrid-like bird we have on record in whichthe distinction from Black-lootedwas unclear. Without behavioral information, this bird's identification mustbe left unresolved. The line between pale hybrids and Laysans isless dear. We haveencountered a small number of adults that appear to be intermediate between hybridsand typical Laysans. Individuals such as the one depicted in Figure18, whichshowed extensive dark smudging onthe flanks, avery l•aint gray wash on the head,and very dark underwings, may be F 2 back-crosses. In 2000, we were able to followone of the chicks attended byan adult hybrid and a pureLaysan through to fledging,and it resembledthe bird in Figure18 in itsextent of extralimitaldark- ness.On the otherhand, such birds could represent anomalous plumages or extremesin variationamong pure birds or hybrids.We have observed similar indi- vidualswith more extensively dark bellies or slightly darker heads than this bird, so thereis no clear line separating "typical" gray hybrids from paler individuals. We havealso seen birds that are slightly paler and more Laysan-like than the bird in Figure14. This is a "classic"hybrid with a contrastinggray head and breast and Figure18, making the dark extreme in "pure"Laysans difficult to pinpoint.The extensivelywhite underparts. This bird shared incubation duties with a Laysan Albatrossin December1999 at Midway.Photograph by JenniferW. Schramrn.

VOLUME 56 (zoOz), NUMBER 2 135 amountof darksmudging on the thighs, flanks, and undertail coverts of Laysan showsa considerableamount of variation.Unlike Whittow (1993b), we have found noevidence, based on examination ofknown-age birds, that this smudging ismore extensiveon juveniles than adults. There appears to bea continuousgradation or overlapbetween typical Laysans and suspected back-crosses inboth flank color and underwingpattern (Fig. 20), and the increased pigmentation of most notably dark individualsisevident in bothareas. Birds retaining the pure white head, belly, and upperflanks and some pattern on the underwing probably fall within the range of variationof pureLaysans, but those showing more extensive darkness are difficult tocategorize. Hybridsalso present a potential source of confusion with other albatross species. GeorgeWatson (in Wahl 1970) discussed the identification of these birds in com- parisonwith an immature Short-tailed Albatross photographed offWashington, dtingwhite feathers on the underwings and the darker bill and feet of hybrids(see alsoRoberson 1980). Older Short-taileds develop pale underwings, but like Black- looted,they always lack the distinctive gray cast of hybrids.Size and structural fea- turesare also diagnostic. Although Wahl later expressed doubts about the identity ofthe Washington bird (Helm 1980, Roberson 1986), we feel that the plumage pat- ternand structural features visible in thephotograph strongly support his original Figure15. Presumedhybrids typically associate with LaysanAlbatrosses. conclusion.On the other hand, we concur that the photograph published inHelm Thisbird shows a fairlyeven gray wash through the headand underparts. (1980),originally identified as a Short-tailedbut later as a Black-footedor Black- MidwayAtoll, March 1999. Photographby TristanMcKee. footedxLaysan hybrid (Roberson 1986), is a worn Black-footed. This bird's neck,

Figure18. This bird shows a veryfaint gray wash to thehead and extensive darksmudging on the flanks; it maybe an F 2 backcross.Determining the darkextreme for pureLaysans is problematic.Midway Atoll, April 1999. Figure16. Althoughthis presumed hybrid is at the darkextreme, the grayish Photographby TristanMcKee. castto the headstill distinguishes it from Black-footed. Midway Atoll, March 2000. Photographby TristanMcKee.

Figure19. Unidentifiedalbatross on Laysan Island, February 1995. This bird superficiallyresembles other suspected hybrids, but the head and neck are brownish,closer in colorto Black-footed.The bluish bill tip, pale feet, and extentof whiteon the belly are unusual in our experience for Black-footedbut mightappear on a leucisticbird. Note also the lack of grayin the auriculars, Figure17. A muchpaler presumed hybrid, showing a pearl-graywash on the normallypresent in adult Laysans and presumed hybrids. Photograph from headand breast. Midway Atoll, March 2000. Photographby TristanMcKee. U.S. and WildlifeService files.

136 NORTH AMERICAN BIRDb Black-footedand LaysanAlbatrosses

Figure20. Underwingand rump patterns of LaysanAlbatrosses and presumed hybrids Laysans that are apparently "pure" can show any of theseunderwing patterns,although (1) is extremelyrare and (4) may suggest intregression with Black-footed insome cases. Most presumed F• hybridsshow patterns similar to (3)and (4) or evendarker. All three rump patterns are common in Laysan,while hybrids tend to beclosest to (C). Sketchby TristanMcKee. breast,and upper belly are considerably darker than any hybrid we have encoun- Phoebastriaspecies. The tails of Black-browedand Gray-headed are grayish when tered,and the bill color, head pattern, and extent of white on the lower underparts fresh(Marchant and Higgins 1990), while hybrids share the dark brown tails of appearto be within the range of variation of Black-footed. Black-lootedand Laysan. Worn birds of both genera have similarly dark, brownish Atfirst glance, hybrids may recall gray-headed forths of the Shy Albatross com- tails. Good views of a combination of thesefeatures should allow the identification plex,but their underwing patterns, aswell as size and structure, should prevent con- of nearlyall birds. Observers are strongly encouraged to photographically docu- fusion.More critically, many presumed hybrids show a superficialresemblance to mentany "gray-headed" albatrosses appearing off North America, including suspect- tinmatureBlack-browed (Thalassarche mdanophr?s) and Gray-headed ( T.chrysos- ed Black-looted x Laysan hybrids, which to our knowledge have not yet been docu- roma)Albatrosses. Theunderwing pattern of some hybrids maintains a recogniza- mented near the continent. bleresemblance tothe"average" Laysan pattern, but others retain only an indistinct Despitebeing large and generally easy to identify,albatrosses show complex age- palestrip on the underwing coverts (e.g., see Fig. 2 in Fisher1972), appearing near- relatedand geographic variation in theirplumages. This can cause confusion, espe- ly identicalto darkimmature Black-browed and Gray-headed Albatrosses in this ciallywhen encountered in their, but not our, element: rough . It does not help respect.The head pattern of hybrids can be a closematch for these species aswell, thattwo of the moregenetically stable species, the Black-footedand Laysan althoughthe two southern species are more likely to retaina darkpartial collar, Albatrosses,show extensive individual variation, which is furthercomplicated by whilehybrids usually show some suggestion of the Black-footed's fadal pattern. apparenthybridization. Wehope this paper will stimulate others to continue todoc- Thalassarchespecies differ noticeably atsea from Phoebastria intheir greater caudal umentand understand variation in albatrossplumages throughout the seven seas. projection,that is, longer projection ofbodyand tail behind the trailing edge of the wings(S. N. G.Howell, pers. comm.). The feet of the former do not extend notice- Acknowledgments ablybeyond the tail tip. The feet of North Pacific Phoebastria project well beyond Weextend special thanks to the people of Midway, including U.S. Fish and Wildlife thetail tip when they are extended, but these species often fly with the feet tucked Servicepersonnel Rob Shailenberger,Ken Neithammer, Nanette Seto, Nancy intothe contour feathers. Another important feature is rump color, which is pure Hoffman,Keith Larson, and Aaron Gallagher, as well as Birgit Winning of the whitein Black-browedand Gray-headed (Morlan 1985, Marchant and Higgins OceanicSociety, who all facilitatedour presence and work on theatoll. We are 1990).Only the palest Laysans show this pattern, and we have never seen a hybrid indebtedto DebraShearwater, who has made it possiblefor us to spenda consid- withouta noticeableintrusion of dark ontothe upperrump (cf. Fig. 20). erableamount of timeoffshore California studying albatrosses on Consideringthat old male Black-footeds canalso be white-rumped, however, this Journeystrips; she also provided valuable photos for use in thispaper. We thank patternis not inconceivable onhybrids. RichStallcup, Michael Donahue, Jennifer Schramm, James Aliberti, and the Otherpotentially useful features toexamine on confusing birds are exact bill and NorthwesternHawaiian Islands National Wildlife Refuge for contributing useful tailcolors. Very young Black-browed and Gray-headed Albatrosses initially show photographsand permission to publish them, and we are most grateful to Cindy blackishbills, but birds of this age are unlikely to be encountered inNorth America. LaFrancefor grantingpermission for us to usethe photograph of thelate Serge Thebill of Black-browedquickly develops a dull pinkish cast at thebase, before LaFrance.Kimball L Garrett,Steve N.G. Howell, Hiroshi Hasegawa, and Joseph changingto yellowishor hornwith a darktip (S.N. G.Howell, pets. comm.; cf. Smithhave added helpful and interesting discussion or information relating to Pattesonet al. 1999).During the brief period when dull pink is evident, the bill thesespecies. Steve N. G.Howell and E A. Buckleyreviewed drafts of themanu- appearsvery similar to that of presumedBlack-footed x Laysan hybrids. scriptand added many helpful suggestions. Developingyellow or horn coloration isindicative ofBlack-browed, butbeware of hybridsilluminated bylow-angle sunlight, which can appear to have yellow tints to Literaturecited theirbills. Gray-headeds develop yellowish or horncoloration along the culmen Bourne,W.R.E 1982.The colorof the tail covertsof the Black-footedAlbatross. andat thetip of themaxilla, a patternthat is easilydistinguished from that of Sea Swallow 31: 61.

VOLUME 56 (2002), NUMBER 2 137 Buckley,P.A. 1969. . Pp. 23-43, in: Diseases inCage Sibley,D. 2000.The Sibley Guide to Birds. Alfred A. Knopf,New York. andAviary Birds, ed. M.L. Petrak.Lea and Febiger, Stallcup,R.W. 1976. Pelagic birds of Monterey Bay, California. Western Birds 7: 113-136. Philadelphia. Stallcup,R., and S. Terrill. 1996. Albatrosses andthe Cordell Bank. Birding 28: 106-110. Cole,L W.2000. A firstShy Albatross, Thalassarche cauta, Streets,T.H. 1877.Contributions tothe natural history of the Hawaiian and Fanning islands and Lower m California and a critical re-examinationof Northern California.Bulletin of the United States Natural History Museum 7:1-172. Hemisphererecords of the formerDiomedea cauta Wahl,T. R. 1970. A Short-tailedAlbatross record from Washington State. California Birds 1:113-115 complex•North American Birds 54: 124-135. Whittow,C. 1993a.Black-looted Albatross (Diomedea nigripes). In:The Birds of North America, No 65 Cousins,K., and J. Cooper. The population biology of the (A. Pooleand E Gill, eds.),Philadelphia Academy of NaturalSciences and the American Black-footedAlbatross in relation to mortalitycaused Ornithologist'sUnion, Washington, D.C. by longlinefishing. Western Pacific Regional Whittow,C. 1993b. Laysan Albatross (Diomedea immutabilis). In:The Birds of North America, No. 66 (A ManagementCouncil, 1164 Bishop St., Honolulu, HI Pooleand E Gill,eds.), Philadelphia Academy of NaturalSciences and the American Ornithologist's 96813.120 pp. Erickson,R•.• andR.A. Hamilton. 2001. Report of the Union,Washington,D.C. z• California Bird Records Committee: 1998 Records. WesternBirds 32: 13-49. Fisher,H.I. 1948.Interbreeding of Laysanand Black- footedalbatrosses. Pacific Science 2: 132. Fisher,H.I. 1971.The Laysan Albatross: its incubation, AviSyg Version 5 hatchingand associatedbehaviors. Living Bird 10: As SimpleAs YouWish ~ As PowerfulAs YouNeed 19-78. F•sher,H.I. 1972.Sympatry of Laysanand Black-footed Seeour web site for greatnew features! Albatross.Auk 89:3 81-402. PalmSupport! Clements' 2001Taxonomy! Support! Harrison,P. 1983., An IdentificationGuide. HoughtonMifflin, . New!Over 2,000 Formal Places, Unlimited Locations! Helm, R.C. 1980.A Short-tailedAlbatross off California. TheLeader ~ Alwaysa GiantStep Ahead of AllThe Rest! WesternBirds 11: 47-48. AviSysis a full-featuredworldwide database and reporting system for serious bird- Howell,S.N.G., and C. Corben.2000. A commentaryon ers.It canbe enhancedby addingthe OfficialShawneen Finnegan Worldwide Na- moltand plumage terminology: implications from the tionChecklist Add-On (as providedin BirdAreaby SantaBarbara Software Prod- Western . WesternBirds 31: 50-56. ucts),providing the most authoritative, highest quality, and most up-to-date check- Jobling,J•. 1991.A Dictionaryof ScientificBird Names. listsof the254 nations of theworld. The checklists are tightly and seamlessly inte- OxfordUniversity Press, Oxford. gratedwith AviSys, providing beautiful screen and printed output with seen, seen- Marchant,S., and P.J.Higgins, co-ordinators. 1990. in-nation,and endemic markers, and instant worldwide nation-by-nation range query Handbookof Australian, and forany species. AviSys produces seen reports, checklists and hit lists of anynation B•rds Volume 1: Ratitesto , Part A. Oxford or state,any group of nationsor states,and all ABARegions and Areas. UniversityPress, Oxford. Youcan instantly reduce the on-screen list from a worldor NAlist to thechecklist of McKee,T., andR. A. EricksonIn press.Report of the anynation, state, county, wildlife refuge, etc., whether provided by AviSysor cre- Cahfornia Bird Records Committee: 2000 records. atedby you. Dealwith only the birds you need. Rotate through modes instantly. WesternBirds 33. OneAviSys user wrote: "OUTSTANDING! I have been a computerprofessional forover 30 Mlchener,H., andJ.R. Michener. 1938. Bars in flight yearsand must congratulate you on generatingstate-of-the-art, convenient to use, effi- feathers. The Condor40:149-160. cientand reliable software." Another says: "AVISYS IS A BLAST!"Precisely our objective Miller, L. 1940. Observationson the Black-footed ß UnlimitedNumber of Lists:all major geographic lists automatically updated. Albatross. The Condor42:229-238. Example:assigning a sighting to youryard also updates your City, County, State, Morlan,J. 1985.Eighth report of the CaliforniaBird Nation,Continent, worldwide ABA Area, worldwide ABA Region, and Life lists. RecordsCommittee. WesternBirds 16: 105-122. -,1(- FullABA N.A. Checklist, Clements World Checklist, and Official Tony White NationalGeographic Society. 1999. Field Guide to the Birds State/ProvinceChecklists, all fullyintegrated with screen and report facilities ofNorth America, 3rd ed. National Geographic Society, -,1(- TheFastest, Easiest and MostFlexible sighting entry•ust click on the birds. Washington,D.C. AviSyshas absolutely unmatched search facilities, including World Band Codes! Patteson,J.B., M. A. Patten,and E. S. Brinkley. The Black- • UnlimitedReporting and Listing by date range, season, geography, species, browedAlbatross in North America: first photographi- habitat,behavior, sex, nesting status, heard-only, photographed, key-words, etc. callydocumented record. North American Birds 53: 228- ß CensusSpreadsheets forpopulation, sighting, CBC, and studies. 231 ß Free!NABA Butteally, Dragonfly, Reptile/Amphibian, and data sets! Roberson,D. 1980. Rare Birds of the West Coast. Woodcock • BirdBaseusers -- askfor our free comprehensive data conversion facility. Pubhcations,Pacific Grove, California. Roberson,D. 1986.Ninth report of theCalifornia Bird Visitour web site at: www.avisys.net RecordsCommittee. WesternBirds 17: 49-77. 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